Knapsack having a one-piece shoulder-blade pad element

ABSTRACT

The knapsack of the invention comprises a one-piece shoulder-blade pad element ( 2 ) whose base for bearing against the back ( 13 ) of the knapsack ( 1 ) is constituted by a reinforcing plate which has a central zone ( 3 ) fixed to the back ( 13 ) of the knapsack in the top middle portion thereof, and two side zones ( 4 ) of oblong shape which extend the central zone ( 3 ) symmetrically both sideways and obliquely downwards. Shoulder-blade pads ( 8 ) are placed in the two side zones ( 4 ) on the reinforcing plate so as to bear against the back of the user over the shoulder blades. Shoulder straps ( 9 ) are fixed to the top edges ( 12 ) of the one-piece shoulder-blade pad element ( 2 ) in its two side zones ( 4 ).

The present invention relates to a knapsack with a particular structurefor bearing against the back to provide the user with better comfort andthe knapsack with better stability.

A knapsack comprises a bag and carrier means including shoulder strapsand a belt. When the knapsack is in use, it is the posterior face of thebag, referred to herein as the “back” of the bag, which comes intocontact with the back of the user. The shoulder straps are fixed to thetop of the back of the knapsack either directly to the materialconstituting said back or optionally to a central device enabling theheight of said straps to be adjusted, as described in document FR 2 668345.

The weight of the knapsack is supported in part by the zone where thestraps bear against the shoulders, and special means are implemented fordistributing load via the belt. Although it is possible to providepadding between the shoulder strap and the shoulder, the Applicant findsthat does not provide the user with a desirable amount of comfort.

Proposals have already been made in document EP 0 122 764 to improveback comfort by fitting the knapsack with shoulder-blade pads which arelongitudinal sleeves filled with padding and slidably mounted on twovertical rods which form the stiffening structure of the knapsack. Theshoulder straps connect the two shoulder-blade pads to the bag.

The knapsack of document EP 0 122 764 does indeed improve user comfortto some extent, however it requires a special knapsack-stiffeningstructure with two vertical rods.

The object of the present invention is to provide comfort that isfurther improved without requiring such a knapsack-stiffening structure.

This object is fully achieved by the knapsack of the invention whichcomprises, in the manner disclosed in document EP 0 122 764, a bag, twoshoulder-blade pads, and two shoulder straps connecting the twoshoulder-blade pads to the bag.

In characteristic manner, it comprises:

a) by a one-piece shoulder-blade pad element comprising a reinforcingplate having a central zone and two side zones extending the sides ofthe central zone symmetrically about the midplane of the knapsack;

b) in that the shoulder-blade pads are disposed in the two side zones onthe reinforcing plate and are shaped to bear against the shoulder bladesof the user; and

c) in that the reinforcing plate is secured to the back of the knapsacksolely via the central zone in the top middle portion of the back.

Thus, by means of the special configuration of the invention, when theknapsack is in use, it is supported near the top of the back not onlyvia the shoulder straps themselves, but also via two shoulder-bladepads, with the load being distributed uniformly over the two shoulderblades by means of the reinforcing plate, even though the knapsack issecured solely via the central zone.

In a preferred embodiment, the connection between the one-pieceshoulder-blade pad element and the knapsack is provided with the abilityto allow the one-piece element to pivot to a certain extent relative tosaid back about an axis perpendicular to said back. This ability topivot provides a degree of independence between the natural movements ofthe user's body and those of the bag.

In a variant where the back of the knapsack is made of a flexiblematerial, the central zone of the one-piece shoulder pad element(including its reinforcing plate) is entirely secured to said material,e.g. by stitches, or by self-gripping mechanical attachment elements ofthe hook-and-loop type, with the ability to pivot being obtained by theability of said material to deform about the connection zone. Under suchcircumstances, the back of the knapsack preferably includes at least onestiffening element at a short distance above the connection zone. Bymeans of this stiffening element, which can be located at a distance dof about 1 centimeter (cm) for example, the angular extent of thepivoting is limited. This stiffening element can consist in particularin a strap sewn transversely to the cloth constituting the back of theknapsack, said strap serving as a connection point for a handle fortaking hold of the knapsack.

In order to further improve application of the two shoulder-blade padsagainst the user's shoulder blades, the reinforcing plate is slightlycurved so that the side zones are spaced a little apart from the back ofthe knapsack when in use, thereby allowing for a certain amount of airflow. When the knapsack is full it is generally of a bulging shape whichis curved in the opposite direction to the natural curvature of user'sback. The particular configuration of the one-piece shoulder-blade padelement conforms completely with these differences of curvature.

In an embodiment, the reinforcing plate is made of a material that isrigid or semi-rigid, e.g. a high density foam which is covered in thetwo side zones by an aerated and damping material constituting thepadding of the shoulder-blade pads, e.g. a superposition of a mediumdensity foam and a porous foam that allows air to flow.

The present invention will be better understood on reading the followingdescription of two embodiments of a knapsack having a one-pieceshoulder-blade pad, as shown in the accompanying drawings, in which:

FIG. 1 is a view showing the back of a first embodiment of a knapsack;

FIG. 2 is a fragmentary diagrammatic view of the first embodiment of theknapsack as seen from above, showing the one-piece element in sectionthrough a shoulder-blade pad when on the back of the user; and

FIG. 3 is a fragmentary diagrammatic view of the back of a secondembodiment of the knapsack.

With reference to FIG. 1, the knapsack 1 of the invention ischaracterized by the presence of a one-piece shoulder-blade pad element2 which alone provides back support while the knapsack 1 is being worn,even though it is fixed thereto in a central zone only.

The one-piece element 2 has three distinct zones, namely: a central zone3 and two side zones 4 which are symmetrical about a plane containingthe middle axis DD′ of the element 2 and also of the knapsack 1.

By way of non-exclusive example, the central zone 3 is rectangular inshape with its long sides extending in the vertical direction of theknapsack, parallel to the axis DD′, while its short sides 6 extendacross the width of the knapsack, perpendicular to the axis DD′.

Each of the side zones 4 is designed to bear against one of the shoulderblades of the user while the knapsack is being worn. In the firstembodiment shown in FIG. 1, each of the two side zones 4 is oblong inshape extending sideways from the central zone and obliquely towards thebottom of the knapsack.

A reinforcing plate 7 (visible in FIG. 2) constitutes the basis of theone-piece element 2, said plate extending both in the central zone 3 andin the two side zones 4, and giving the above-mentioned special shape tosaid one-piece assembly.

A pad 8 is placed in each side zone 4 increasing the thickness of thereinforcing plate 7 and designed to come into contact with the user'sback while the knapsack is being worn.

In conventional manner, the knapsack 1 has two shoulder straps 9 and abelt 10. The shoulder straps 9 are not fixed to the bag 11 but to theone-piece shoulder pad element 2 via the top edges 12 of the side zones4. In the example shown (which is for the European market), thisconnection is made as far away as possible from the central zone 3. Theposition of this connection can vary depending on the averagemorphology-of users.

The opposite ends of the shoulder straps 9 are secured to low portionsof the knapsack, close to the belt 10.

The bag 11 is secured to the one-piece shoulder-blade pad element 2 viathe central zone 3 of said element 2. This connection is preferably madeso as to provide the element 2 with the ability to pivot to some extentrelative to the back 13 of the knapsack, as shown by arrow F.

When the back 13 of the knapsack is made of a flexible material, inparticular a cloth, this ability to pivot is obtained very simply bystitches or any other fastening means between all or part of the zone 3of the one-piece element 2 and said material constituting the back 13.The pivoting is then made possible by natural deformation of theflexible material.

Nevertheless, in order to limit this deformation, it is preferable tostiffen the back portion 13 that lies in the vicinity of the connectionzone, as in the example shown. By way of example, stiffening can beprovided by a strap 14 sewn transversely to the top of the back 13 at asmall distance from and parallel to the top short side 6 of the centralzone 3. This strap can be used to secure a handle 15 for carrying theknapsack 1. Deformation of the flexible material above the connectionzone is thus smaller than its deformation beneath the connection zone soas to obtain smaller angular displacement in the vicinity of thestiffening element 14, which displacement is preferably centered on theaxis DD′.

As shown in FIG. 2, the reinforcing plate 7 is preferably curved, atleast in the two side zones 4 so that the one-piece element 2substantially matches the natural curvature of the back and so that theshoulder-blade pads 8 make uniform contact over their entire surfacearea with the back of the user via the shoulder blades.

The shoulder-blade pads 8 are padded with foam that increases thethickness of the reinforcing plate 7. This can comprise a superposedplurality of layers of foams of different structures, e.g. a first layer16 of medium density foam that is in contact with the reinforcing plate7, and a second layer 17 of low density foam with open pores.

The reinforcing plate 7 and the layers of foam 16, 17 are placed insidea cover 18, with the entire assembly constituting the one-pieceshoulder-blade pad element 2. The cover 18 is preferably perforated overthe second layer of foam 17 so as to allow air to pass through, therebyventilating the shoulder-blade pads to some extent and removing thesweat that they can absorb while the knapsack is being worn.

The reinforcing plate 7 must be sufficiently rigid firstly to transferload between the central zone secured to the back of the knapsack andthe shoulder straps fixed to the side zones, and secondly to allow theone-piece assembly 2 to pivot uniformly relative to the knapsack.However there is no need for it to be completely rigid, and it can flexto a small extent as shown by arrow G.

FIG. 2 shows the position of the one-piece element 2 while the knapsack1 is being worn. The user's back is contacted solely through the sidezones 4 of the one-piece element 2, with the curvature of thereinforcing plate 7 making it possible for back contact to bedistributed uniformly over this entire area. It can be observed that theknapsack 1, when full, takes up a bulging shape which curves in theopposite direction to the curved shape of the user's back 19, so that anempty space 20 is left between the knapsack and the one-piece element 2on either side of the connection zone 2, thus enabling the wearer's backto be ventilated by a flow of air.

The maximum weight of the one-piece element 2 can be greater than thewidth of the back 13 of the knapsack, particularly with a small-volumeknapsack.

The central zone 3 is secured to the back 13 of the knapsack 1 bystitching along the four sides 5, 6 of the central zone 3 and also alongthe two diagonals of the corresponding rectangle. Such connection bystitching is easily implemented along the two small sides 6 of the cover18. Along the two long sides and along the diagonals, it is necessaryalso to stitch through the reinforcing plate. This can be done by usinga plate made out of high or medium density foam while neverthelessensuring that it is sufficiently rigid to obtain the desired technicaleffect.

The second embodiment of a knapsack 20 of the invention is shown in partin FIG. 3 which relates essentially to a one-piece shoulder-blade padelement 21 of a configuration that is different from that of the firstembodiment. As before, this one-piece element 21 has a central portion22 of rectangular shape with its long sides 23 extending longitudinallyalong the middle axis DD′ of the knapsack while its two short sides 24extend across said axis DD′. In a preferred embodiment, the central zone22 via which the one-piece element 21 is secured to the back 25 of theknapsack 20 has long sides 23 that are about 8 cm to 12 cm long, andshort sides 24 that are about 4 cm to 6 cm long.

The side zones 26 of the one-piece element 21 extend on either side ofthe central zone 22 and they project towards the top of the knapsack,with the end portion 26 a of each projection acting as a shoulder strap.

In each side zone 26, the shoulder-blade pad 27 has an oblong shapewhich extends over the side zone 26, including into the upwardprojection thereof up to the end portion 26 a.

The reinforcing plate extends over the entire area of the one-pieceelement 21, including within the end portions 26 a that form shoulderstraps. Towards the tip 28 of each end portion 26 a there is provided abuckle 29 for receiving a strap suitable for connecting the one-pieceelement 21 to the bottom portion of the bag. The end portions 26 a canalso be padded.

In the embodiment shown in FIG. 3, the one-piece shoulder-blade padelement 21 is secured to the back 25 of the knapsack 20 by mechanicalfastener elements of the self-fastening type, using hooks and loops.More particularly, the central zone 22 of the one-piece element 21 hasloop elements on the outside, provided in particular by sewing a stripof cloth 30 having loops both on the outside face and on the inside faceto the central zone 22 of the outer covering of the one-piece element21.

Furthermore, in the top middle portion of the back 25 of the knapsackthat corresponds to the zone for securing said back 25 to the one-pieceelement 21, there are provided elements that have hooks. In the exampleshown in FIG. 3, this comprises a strip 31 of length L that issubstantially three times longer than the long side 23 of length 1 ₁ ofthe central rectangular zone 22. The strip 31 does, however, have thesame width 1 ₂ as the short side 24 of the central zone 22. This strip31 presents hooks on its outside face and loops on its inside face, andit is sewn onto the back 25 of the knapsack solely in its middle portion31 c that corresponds to the surface of the central zone 22. The twoends 31 a and 31 b of this strip 31 that are not sewn to the back 25 ofthe knapsack are therefore free.

The one-piece shoulder-blade pad element 21 is secured to the knapsackby pressing its central zone 22 against the sewn middle portion 31 c ofthe strip 31 so that the loops on the inside face of the central zone 22co-operate with the hooks carried by the middle portion 31 c of thestrip 31.

The bottom end 31 b of the strip 31 is raised towards the central zone22 so that the hooks carried by this end 31 b co-operate with theoutside loops carried by the strip 30 covering the central zone 22.Thereafter the top end 31 a is moved down in turn to cover the bottomend 31 b. Since the strip 31 has loops on its inside face, the hookscarried by the top end 31 a co-operate with said loops, thereby lockingthe central zone 22 of the one-piece shoulder-blade pad element 21definitively in position on the back 25 of the knapsack 20. This elementcan be removed by performing the same operations in the opposite order.

This method of connection means that the one-piece shoulder-blade padelement is not definitively secured to the bag, thus making it possiblewhen the knapsack is sold to give the user the opportunity to assemble adesired knapsack by selecting a best-fit one-piece shoulder-blade padelement and by selecting the desired type of bag.

The present invention is not limited to the preferred embodimentdescribed above by way of non-exhaustive example. In particular, the waythe central portion 3 of the one-piece shoulder-blade pad element 2 issecured with the ability to pivot can be obtained by other means,optionally using intermediate fastening pieces that provide for angularmovement.

The term “one-piece” as used herein merely means that the shoulder-bladepad element comprises a single piece; this term does not exclude theelement in question itself being made up from a plurality of independentparts that are assembled together, as can be seen from the abovedescription.

What is claimed is:
 1. A knapsack comprising: a bag; a one-pieceshoulder-blade pad element comprising firstly a reinforcing plate havinga central zone and two side zones which extend the central zone sidewayssymmetrically about the midplane of the knapsack, and secondly twoshoulder-blade pads placed in the two side zones on the reinforcingplate and shaped to bear against the shoulder blades of the user; andtwo shoulder straps connecting the two shoulder-blade pads to the bag,wherein the reinforcing plate is secured to the back of the knapsacksolely via the reinforcing plate central zone in the top middle portionof the back.
 2. A knapsack according to claim 1, characterized in thatthe reinforcing plate is slightly curved so that the side zones areslightly spaced apart from the back of the knapsack when in use.
 3. Aknapsack according to claim 1, characterized in that the reinforcingplate is made of a rigid or semi-rigid material which is covered in thetwo side zones in an aerated and damping material constituting thepadding of the shoulder-blade pads.
 4. A knapsack according to claim 3,characterized in that the reinforcing plate is made of high density foamwhich is covered in the two side zones by medium density foam and byporous foam that allows air to flow.
 5. A knapsack according to claim 1,characterized in that the connection between the one-pieceshoulder-blade pad element and the back of the knapsack is provided withthe ability to allow the one-piece element to pivot to a certain extentrelative to said back about an axis perpendicular to said back.
 6. Aknapsack according to claim 5, characterized in that the central zone isrectangular in shape having a short side of about 4 cm to 6 cm acrossthe width of the knapsack and a long side of about 8 cm to 12 cm alongthe height of the knapsack.
 7. A knapsack according to claim 5,characterized in that the back of the knapsack is made of flexiblematerial and the central zone is fixed to said flexible material in afixing zone, the ability to pivot being obtained by the ability of saidmaterial to deform about said connection zone.
 8. A knapsack accordingto claim 7, characterized in that the central zone is secured to theflexible material by stitches.
 9. A knapsack according to claim 8,characterized in that the central zone is rectangular in shape having ashort side of about 4 cm to 6 cm across the width of the knapsack and along side of about 8 cm to 12 cm along the height of the knapsack.
 10. Aknapsack according to claim 8, characterized in that: the back of theknapsack has at least one stiffening element at a short distance (d)above the connection zone; the stiffening element is constituted by astrap sewn transversely to the flexible material forming the back of theknapsack at a distance (d) equal to about 1 cm; the reinforcing plate isslightly curved so that the side zones are slightly spaced apart fromthe back of the knapsack when in use; the reinforcing plate is made of arigid or semi-rigid material which is covered in the two side zones inan aerated and damping material constituting the padding of theshoulder-blade pads; and the reinforcing plate is made of high densityfoam which is covered in the two side zones by medium density foam andby porous foam that allows air to flow.
 11. A knapsack according toclaim 7, characterized in that first and second fastening means areprovided respectively on the flexible material and on the central zoneso as to secure the one-piece shoulder-blade pad element to the back ofthe knapsack by co-operating.
 12. A knapsack according to claim 11,characterized in that the first and second fastening means are providedwith self-fastening mechanical attachment elements comprising hooks andloops.
 13. A knapsack according to claim 11, characterized in that theback of the knapsack has at least one stiffening element at a shortdistance (d) above the connection zone.
 14. A knapsack according toclaim 13, characterized in that the stiffening element is constituted bya strap sewn transversely to the flexible material forming the back ofthe knapsack at a distance (d) equal to about 1 cm.